The Internet has nearly a ten year history as a global, public communication infrastructure. The two applications that have created the demand from private and business users have been the World-Wide Web and electronic mail. We have inthelast?veyearsseentherapidlyemergingpopularityofpeer-to-peersharing of ?les, mostly for music, and to a more limited extent also the introduction of Internet telephony, television, and radio. These services place demands on the infrastructure that are higher with respect to quality and connectivity than web sur?ng and e-mail. Mobile (cellular) telephony has rivaled the Internet with respect to growth during the last decade. The hitherto separate networks are now set to merge into a mobile Internet that will give wireless access to all Internet services. The ambition behind the Internet’s continuing development is that it should serve as a general-purpose infrastructure and provide adequate support for all types of applications in terms of quality, connectivity, and cost. Thus the demands made on all Internet services must also be met by wireless access, and the circuit quality of a voice connection for mobile telephony must also be provided in the wiredIPnetworks.